318SixPack

Back on 12/01/2021 I was resetting the CEL every other day, had been going on for a while, only code was CAT efficiency.
Put in a bottle of CATACLEAN per instructions (add it at 1/4 tank, drive 10-15 miles, fill up tank).
Didn't get CEL again (same fault) until yesterday 12/12/2021. Added another can right after CEL came on and reset code. Will see if this does anything.

Saw a Scotty Kilmer video of doing the same thing with a gallon of mineral spirits. But I am not on board with that method, as I am not familiar enough with what that material does to the rest of the fuel system.

Will report back on how this goes.

IJM

Have you tried an Italian tune-up while you're at it? That often helps to get the cat good and hot.

robsjeep

Code for a bad catalyst are generated by oxygen sensors. sensor might be bad. Since oxygen is measured, an exhaust leak might alter oxygen content.

318SixPack

I did keep it up around 2k RPM most of the drive, just used a lower gear than usual.

318SixPack

I seriously doubt that the downstream sensor is bad, then not bad, then bad again. Not seeing where an exhaust leak is/could happen between sensors either.

doublechaz

You could have a leak after the upstream sensors but before the downstream sensor. But that would let in oxygen which would make your cat work better than normal unless literally every bit of platinum and palladium is burned out of your cats and they are just wide spots in the pipe, but that would mean that your bottle of cat treatment stuff would have zero effect.

IJM

LOL, no.

What you want is full throttle and high revs to get everything good and hot so you can burn the carbon out and get it purring sweetly. Find yourself a good long hill on highway, and do a few full throttle pulls through the gears to or near redline. At higher speeds you'll accelerate more slowly, so you can spend more time at WOT. Just don't blame me if you get a ticket. ;-)

318SixPack

I'm already on record here as being too chicken for high RPM driving.

Ralph77

You and me both.
I did 90 MPH once for under a minute once.
Oh hell probably under 30 seconds.
On a long, flat, straight stretch of highway.
Will be the first and last time I do that.
Jeep was fine. I was the one that was uncomfortable. LOL.
80 MPH is a decent cruising speed IMO.

cruiser54

2000? Let's see 3500 to 4000. It has a 4800 RPM redline for crying out loud!!

I've driven them with the speedo needle pointing straight down.
I've held them for 4 minutes straight at 4000 RPM to free up lifters. I'm still driving these vehicles. Over 200K miles. You guys need to get over your phobias.......

IJM

Seriously. I've long been a proponent of driving cars gently until they're fully warmed up (the oil, not just the coolant) and then not being afraid to give it the beans once in a while (or regularly). My VW probably has close to 30k miles of flat-out driving around the track, and it still purrs like a kitten and burns no oil. You've gotta run 'em hard and treat them right.

fb97xj1

If you dont want to go fast on the road, pull a Cameron and use a jackstand like he did with that Ferrari. Except use 4 jackstands, and rev the snot out of it. No kicking! If it isnt on the road, its not really speeding.

robsjeep

You dont need to break the law by speeding. Instead go fast in 3rd or 2nd gear, get the revs up.

how many miles on the cat?
How many miles on the O2 sensor?

cruiser54

That's too simple and obvious. We need something more complicated we can research and then pooh-pooh good old common sense from seasoned folks with real world experience.

I know the fix. I've done it. But, I'm sure I had mine fixed in less time than I've spent responding to this thread.

318SixPack

The red on my tachometer starts at 5250 rpm.